Journal of Power Electronics

The Korean Institute of Power Electronics (전력전자학회)
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Improved neutral shift method for fault tolerant operation of three phase MLCI

  • Kim, Jeongwoo (Department of Electrical and Electronic Engineering, Konkuk University) ;
  • Cho, Younghoon (Department of Electrical and Electronic Engineering, Konkuk University)
  • Received : 2020.08.06
  • Accepted : 2020.09.15
  • Published : 2021.01.20
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Abstract

In a three-phase multilevel cascaded inverter (MLCI), when a failed module is bypassed, the number of modules in each phase becomes unbalanced. Under this condition, a method to obtain a balanced three-phase output is to move the neutral point of the MLCI. The neutral-point shift (NS) method has attracted a great deal of attention since the output of the inverter has a relatively low harmonic distortion when compared to other fault-tolerant operation methods. To move the neutral point, an offset voltage of the fundamental frequency component is injected. If the injected offset voltage exceeds the available range of the offset voltage, overmodulation occurs. Then, the output of the inverter is distorted. In this paper, the overmodulation regions of the NS method are analyzed for the fault-tolerant operation in the three-phase MLCI. In addition, a modified NS method is proposed to compensate for the overmodulation region. Both simulation and experimental results in a two-by-three MLCI demonstrate the performance of the proposed method.

Keywords

Acknowledgement

This work was supported by "Human Resources Program in Energy Technology" of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry and Energy, Republic of Korea. (No. 20194030202370). This research was supported by the Human Resource Program (Grant No. 20194010201790) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Ministry of Trade, Industry and Energy (MOTIE) of the Republic of Korea.

References

  1. Mittal, N., Singh, B., Singh, S. P., Dixit, R., Kumar, D.: (2012) Multilevel inverters: a literature survey on topologies and control strategies. 2012 2nd international conference on power, control and embedded systems, Allahabad, pp. 1-11
  2. Abu-Rub, H., Holtz, J., Rodriguez, J., Baoming, G.: Medium-voltage multilevel converters-state of the art, challenges, and requirements in industrial applications. IEEE Trans. Ind. Electron. 57(8), 2581-2596 (2010) https://doi.org/10.1109/TIE.2010.2043039
  3. Kouro, S., et al.: Recent advances and industrial applications of multilevel converters. IEEE Trans. Indu. Electron. 57(8), 2553-2580 (2010) https://doi.org/10.1109/TIE.2010.2049719
  4. Rodriguez, J., Lai, J.-S., Peng, F.Z.: Multilevel inverters: a survey of topologies, controls, and applications,". IEEE Trans. Ind. Electron. 49(4), 724-738 (2002) https://doi.org/10.1109/TIE.2002.801052
  5. Rodriguez, J., Pontt, J., Musalem, R., Hammond, P.: Operation of a medium-voltage drive under faulty conditions. The 4th international power electronics and motion control conference, 2004. IPEMC 2004, Xi'an. 2, 799-803 (2004)
  6. Hammond, P., Aielo, M. F.: Multiphase power supply with plural series connected cells and failed cell bypass. U.S. Patent 5986909, Nov. 16 (1999)
  7. Hammond, P.W.: Enhancing the reliability of modular medium-voltage drives. IEEE Trans. Ind. Electron. 49(5), 948-954 (2002) https://doi.org/10.1109/TIE.2002.803172
  8. Lezana, P., Ortiz, G.: Extended operation of cascade multicell converters under fault condition. IEEE Trans. Ind. Electron. 56(7), 2697-2703 (2009) https://doi.org/10.1109/TIE.2009.2019771
  9. Maharjan, L., Yamagishi, T., Akagi, H., Asakura, J.: Fault-tolerant operation of a battery-energy-storage system based on a multilevel cascade pwm converter with star configuration. IEEE Trans. Power Electron. 25(9), 2386-2396 (2010) https://doi.org/10.1109/TPEL.2010.2047407
  10. Song, J., Zhang, W., Liang, H., Jiang, J., Yu, W.: Fault-tolerant control for a flexible group battery energy storage system based on cascaded multilevel converters. Energies 11, 171 (2018) https://doi.org/10.3390/en11010171
  11. Carnielutti, F., Pinheiro, H., Rech, C.: Generalized carrier-based modulation strategy for cascaded multilevel converters operating under fault conditions. IEEE Trans. Ind. Electron. 59(2), 679-689 (2012) https://doi.org/10.1109/TIE.2011.2157289
  12. Ouni, S., et al.: Improvement of post-fault performance of a cascaded h-bridge multilevel inverter. IEEE Trans. Ind. Electron. 64(4), 2779-2788 (2017) https://doi.org/10.1109/TIE.2016.2632058
  13. Salimian, H., Iman-Eini, H.: Fault-tolerant operation of three-phase cascaded h-bridge converters using an auxiliary module. IEEE Trans. Ind. Electron. 64(2), 1018-1027 (2017) https://doi.org/10.1109/TIE.2016.2613983
  14. Kumar, B.H., Lokhande, M.M., Karasani, R.R., Borghate, V.B.: Fault tolerant operation of chb multilevel inverters based on the svm technique using an auxiliary unit. J. Power Electron. 18(1), 56-69 (2018) https://doi.org/10.6113/JPE.2018.18.1.56
  15. Song, W., Huang, A.Q.: Fault-tolerant design and control strategy for cascaded h-bridge multilevel converter-based STATCOM. IEEE Trans. Ind. Electron. 57(8), 2700-2708 (2010) https://doi.org/10.1109/TIE.2009.2036019
  16. Wei, S., Wu, B., Rizzo, S., Zargari, N.: Comparison of control schemes for multilevel inverter with faulty cells. 30th Annual conference of IEEE industrial electronics society, 2004. IECON 2004, Busan, South Korea. 2, 1817-1822 (2004)
  17. Aleenejad, M., Iman-Eini, H., Farhangi, S.: Modifed space vector modulation for fault-tolerant operation of multilevel cascaded H-bridge inverters. IET Power Electron. 6(4), 742-751 (2013) https://doi.org/10.1049/iet-pel.2012.0543
  18. Aleenejad, M., Mahmoudi, H., Moamaei, P., Ahmadi, R.: A new fault-tolerant strategy based on a modifed selective harmonic technique for three-phase multilevel converters with a single faulty cell. IEEE Trans. Power Electron. 31(4), 3141-3150 (2016) https://doi.org/10.1109/TPEL.2015.2444661
  19. Aleenejad, M., Mahmoudi, H., Ahmadi, R.: Multifault tolerance strategy for three-phase multilevel converters based on a half-wave symmetrical selective harmonic elimination technique. IEEE Trans. Power Electron. 32(10), 7980-7989 (2017) https://doi.org/10.1109/TPEL.2016.2633230
  20. Neyshabouri, Y., Iman-Eini, H.: A new fault-tolerant strategy for a cascaded H-bridge based STATCOM. IEEE Trans. Ind. Electron. 65(8), 6436-6445 (2018) https://doi.org/10.1109/tie.2018.2793182
  21. Cho, Y., LaBella, T., Lai, J., Senesky, M.K.: A carrier-based neutral voltage modulation strategy for multilevel cascaded inverters under unbalanced DC sources. IEEE Trans. Ind. Electron. 61(2), 625-636 (2014) https://doi.org/10.1109/TIE.2013.2254091